Lately you’ve been listless and lacking your usual energy. Your workouts have been off, your endurance is flagging, and your muscles are sapped the next day. You may chalk it up to the cold weather, but temperature might not be the true culprit. It could be dehydration. What?? It’s ten degrees outside and it’s all you can do to keep warm! But the evidence is there: the cracked lips and dry sinuses, the chapped skin and brittle hair.
During a heatwave, the point is driven home: Stay hydrated! And for good reason. Water is essential to life. It plays a role in everything from brain function and digestion, to staving off stress and fighting illness. Staying hydrated is even more vital when you’re active. Not only do you need to keep replacing the fluids your body loses to sweat, but the water you drink also aids in muscle recovery and helps lubricate joints. But despite all the attention proper hydration receives during the summer months, it’s a year-round issue. In some ways, it’s more important in the winter because cold weather neutralizes the triggers that let you know it’s time to drink water.
In our corner of the country, the winter air is cold and dry. And whether you’re outside exercising, shoveling snow, or simply waiting with the kids at the bus stop, you’re losing fluid while breathing that air. That’s because your body humidifies it, adding moisture and heating it up to your internal temperature (that’s why your breath look like fog in the cold). Even the heated air of your home and office, which is typically drier than outside air, is humidified by your body. On a mild day, you lose between one to two quarts of water by evaporation from the lungs. In cold weather, you lose even more, as your body works harder to humidify and warm the air. The basic task of breathing winter air increases your need for water.
Being active further increases that need. When your body gets warm, it perspires to cool off. Being hot and sweaty triggers thirst, telling your body to drink up. You’ve probably noticed this during the dog days of summer when you’re in the studio and reaching for the water bottle after one song. That thirst is your body telling you to replenish the fluids its losing. On the other hand, at the beginning of a winter class, when the studio is chilly, you may not touch that water bottle until several minutes into your ride. Obviously, that’s because you sweat more in the summer, right? Wrong.
Though it may be hard to believe, you perspire just as much in the winter as the summer. However, in cold, dry air sweat evaporates quickly, cooling you off immediately. You may never feel warm or notice a single bead of sweat. Even worse, you may not get thirsty. In cold temperatures, your body pools blood near its core. This preserves heat and keeps your vital organs warm. But it also tricks your body into thinking it has ample fluids, even as it’s losing water through perspiration. So that thirst signal is never triggered and you go longer than you should without drinking fluid. This phenomena doesn’t just happen on frigid days. Studies show that it occurs at around 40 degrees.
It’s hard enough to get the fluids you need in the summer heat, when you’d kill to cool off with a bottle of water. It can be an absolute chore when the snow is blowing and you can’t stop shivering. But it’s no less important. To keep yourself hydrated and performing your best this winter, drink plenty of fluids throughout the day, especially in the hours leading up to and following workouts. Aim for 6-8 eight ounce glasses (or enough to keep your urine clear). If you have trouble drinking cold fluids in the winter, try a warm beverage like green tea or warm water with lemon. You can also eat foods with high water content, such as tomatoes, broccoli and lettuce. But go light on sugary drinks like soda and juice, which can actually cause dehydration.